VANDENBERG AIR FORCE BASE, CALIF. - Inside the Astrotech Payload Processing Facility on Vandenberg Air Force Base in California, workers help guide the CALIPSO spacecraft as it is lowered onto a payload attach fitting. CALIPSO will be mated to the Lower Delta Payload Attach Fitting (LDPAF) that contains the CloudSat satellite. The PAF is the interface between the spacecraft and the second stage of the rocket. CALIPSO stands for Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation. CALIPSO and CloudSat are highly complementary satellites that will provide never-before-seen 3-D perspectives of how clouds and aerosols form, evolve, and affect weather and climate. CALIPSO and CloudSat will fly in formation with three other satellites in the A-train constellation to enhance understanding of our climate system. Launch of CALIPSO/CloudSat aboard a Boeing Delta II rocket is scheduled for 3:01 a.m. PDT Sept. 29.